EP1226015B1 - Method for producing tubular containers - Google Patents

Abstract

The invention relates to a method for producing tubular containers with an open filling opening and with an end that is provided with a seal. The inventive method comprises the following steps: separately producing a preform with a neck with definitive dimensions and a tubular body with smaller dimensions than the definitive form, the tubular body containing the open filling opening; fixing the preform that is produced to a drawing head by its neck and subjecting it to at least one partial heating process; introducing the heated preform that is attached to the drawing head into the inside of a multi-part closed blow mold in such a way that the open filling opening is air-tightly held at the lower end of the blow mold; fitting a blow nozzle to the filling opening of the preform.

Description

The invention relates to a method for producing containers by producing them separately a preform with a neck of final dimensions and a tubular body with smaller dimensions in relation to the intended final shape, heating the Preform, attaching the preform in the neck area to a drawing head, inserting the preform with the pulling head into the interior of a multi-part closable blow mold, axial pulling of the Preform by means of the drawing head and width of the preform by blowing air into it Interior, hardening of the container lying against the wall of the blow mold, opening of the Blow molding and removing the container as is known from US-A-4,988,399.

According to this known method, two are identical in one operation Container parts made by central separation from a preform open on both sides Intermediate form produced, after which both container parts to finished containers with one each Be provided on the floor.

DE 37 04 264 A1 describes the manufacture of one end open and the other closed plastic hollow body known Two completely different Techniques such as spraying on the one hand and blowing on the other on the same Machine carried out, taking into account that for spraying much longer Times are needed as for blowing, which is related to making them together in one Machine affects. By means of a nozzle, a hose is continuously removed by removing one Puller is pulled from the plastic feed nozzle, due to this supplied blown air is already somewhat expanded. Only when the deliverable blow molded parts can be closed, d. H. if there is a sufficient distance between the off device and the nozzle, through which the supply of plastic and blowing air takes place, is only still blown air supplied to expand the extruded pipe section.

The object of the invention is to restore a method for producing tubular closable containers with closures indicate that the simple Manufacture of any shape of tubular container permitted, even with closed Dispensing opening.

This object is achieved by a method with the features of claim 1.

Advantageous embodiments of the invention can be found in the subclaims.

Fig. 1

verschiedene Preformen, darunter auch solche mit einem außenliegenden Flansch,

Fig. 2

Querschnitte von Preformen,

Fig. 3

die Verbindung einer Preform mit verschiedenen Ziehköpfen,

Fig. 4

das Erwärmen einer Preform durch Strahlungswärme und Heißluft,

Fig. 5

das Einführen einer Preform mittels des Ziehkopfes in eine offene Blasform und das Zuführen einer Blasluftdüse,

Fig. 6

das Schließen der Blasform mit nachfolgendem Anfahren einer Blasdüse an das offene Preformende,

Fig. 7

das Streckziehen und das Vorblasen einer Preform,

Fig. 8

Strecken und Blasen von Preformen mit und ohne Flansch,

Fig. 9

das Entgasen bzw. Entlüften des in der Blasform verbleibenden fertigen Behälters,

Fig. 10

das Öffnen der Blasform und das Entfernung der Blasdüse,

Fig. 11

zwei Ausführungsformen zur Entfernung des unvollständig verformten Endes eines fertigen tubenförmigen Behälters, wobei bei einer Ausführungsform mit der Entfernung des Endes gleichzeitig eine Durchgangsöffnung im Tubenhals hergestellt wird,

Fig. 12

das Entfernen des fertigen Behälters aus dem Ziehkopf,

Fig. 13

Ausführungsformen von tubenförmigen Behältern in Seitenansicht nebst Querscbnitten.

The invention is explained in more detail below using exemplary embodiments with reference to drawings. It shows:

Fig. 1

various preforms, including those with an external flange,

Fig. 2

Cross sections of preforms,

Fig. 3

the connection of a preform with different drawing heads,

Fig. 4

heating a preform using radiant heat and hot air,

Fig. 5

inserting a preform into an open blow mold by means of the drawing head and feeding a blow air nozzle,

Fig. 6

the closing of the blow mold with subsequent moving of a blow nozzle to the open preform end,

Fig. 7

stretching and pre-blowing a preform,

Fig. 8

Stretching and blowing preforms with and without flange,

Fig. 9

degassing or venting the finished container remaining in the blow mold,

Fig. 10

opening the blow mold and removing the blow nozzle,

Fig. 11

two embodiments for removing the incompletely deformed end of a finished tubular container, in one embodiment a through-opening being made in the tube neck simultaneously with the removal of the end,

Fig. 12

removing the finished container from the drawing head,

Fig. 13

Embodiments of tubular containers in side view with cross sections.

In Fig. 1 three preforms are shown, which are each manufactured in separate processes. In Figure 1a, the preform 1 has a tubular body 2 with an open end 3. At the at the other end, the tubular body 2 has a neck 4 for the finished container required dimensions, which are extremely precise and reproducible thanks to the preform must be observed, which is particularly important for closures. In the case of Fig. 1a Preform shown, the neck 4 is closed and has an external thread 5, wherein his tubular body 2 at its open end 3 an outer annular Has flange 6. The preform shown in FIG. 1b corresponds to the one shown in FIG. however, a central dispensing opening 7 is made in the neck 4. That in Fig. 1c The illustrated embodiment corresponds to that shown in FIG. 1a, with the neck 4th is also closed, but has a conical cannula 8.

According to the exemplary embodiments shown in FIG. 2, the preforms 1 can be one have annular or oval cross-section. In addition, angular, z. B. triangular or polygonal cross sections - preferably with rounded corners - possible (not ) Shown. Furthermore, the same or even over the entire cross section different wall thicknesses can be provided. It is Z. B. possible with a container oval cross-section and uniform wall thickness from a preform with a round cross-section and produce uneven wall thicknesses.

FIG. 3a shows a preform 1 according to FIG. 1a, which has a pull rod 9a with a drawing head 9b and a two-part holder 11 can be fed, the latter can also be used to hold Torques serve during a screwing process. In this embodiment, the Pulling head 9b has an internal thread 10 which corresponds to the external thread 5 of the neck 4. The Holder 11 has a central opening 12, 12 ', the outer diameter of the tubular body 2 of the preform 1 equivalent. An annular groove 13 is made within the holder halves 11 ', 11 " serves to accommodate the flange 6 of the preform 1. 3b and c are possible Connections of a preform 1 with a drawing head 9b shown, the according to FIG. 3b Preform 1 fixed and the drawing head 9b rotatable and, according to FIG. 3c, the drawing head 9b not rotatable and the preform 1 are rotatably arranged with the holder 11.

Each preform attached to a drawing head 9b is then a heater 14, which also a heating chamber can be supplied (see FIGS. 4a and b), which can be of any design. As Radiant heat (e.g. infrared radiation) is preferably used, but it is also, for example, the use of hot air, ultrasound or microwaves possible, the heating of the tubular body 2 of a preform 1 over height and Scope can be made evenly or unevenly.

The heated preform 1 attached to the drawing head 9b is inserted into the inside of a Embodiment two-part blow mold 16 (see. Fig. 5) supplied, the Blow mold halves 16 ', 16 "in the closed state (see FIG. 6) make it possible for the Flange 6 of the preform 1 is supported at the lower outer end of the closed blow mold 16. The lower open end 5 of the supported preform 1 is sealed against that Flange 6 fed a blow nozzle 17, the diameter of which is preferably the diameter of the tubular body 2 is adapted.

6, the inner upper end of the closed blow mold 16 adjusted according to the exterior of the drawing head 9b, d. H. the drawing head 9b forms in its part of the blow mold 16.

In Fig. 7 is a through stage of the process of stretch drawing by means of the upward moving head (see arrow) and with the supply of compressed air (under Pre-blowing pressure).

In Fig. 8 has already pulling the pull rod 9a through which the pulling head 9b in its upper end position forming part of the blow mold 16 and stretching of the preform by supplying blown air with a pressure that is preferably higher than the pre-blowing pressure Pressure took place in the final shape, which is predetermined by the blow mold 16a. In Fig. 7b a blow mold 16b is conical with a lower one opening outwards designed area 19 is provided, which serves the lower open end 3 a Preform 1 also without a flange by means of an appropriately conical outer shape a blowing nozzle 17 'to clamp so that when pulling the drawing head 9b in Direction of arrow, the lower open end 3 of the preform 1 is also securely clamped in place is held.

9 is the degassing or venting of the molded container blank shown, which is carried out by the remaining blowing nozzle 17 (see Arrows) until the internal pressure is released.

10 shows the opening of the blow mold 16 and the removal of the blow nozzle 17, by the previous degassing inside the molded container 23 there is atmospheric pressure again.

The finished container has an end part 19 at the lower end, which is not complete is inflated or stretched and not the desired final dimensions of the container produced. This "incompletely" shaped end part 19 becomes by cutting using a knife 20 (see FIG. 11 a) or using a laser beam 21 (see Fig. 11b) separated. Through this cut, the finished container 23 can also Get the desired length. A laser beam 21 can be used by means of a Mirror 22 simultaneously with the separation of the end part 19 also in the closed Neck 4 an outlet opening 7 are made (broken arrow) or first one Made output opening 7 and then the separation of the end part 19 (extended Arrow). The same applies to an opening in a preform 1 with a Cannula 8 (see Fig. 1d).

In a further step, relative rotation between the drawing head 9b and manufactured container 23 or by opening the claws 14 from the finished container 23 the pulling head 9b, wherein a holder 11a in Form of two adjustable holding jaws (see Fig. 12a) or a holder 11b in the form of a Retaining rod (see Fig. 12b) retracted into the interior of the container can, which should prevent the container from rotating.

In Fig. 11 are three different forms of tubular containers 23 and three possible cross-sectional shapes are shown. In Fig. 11a is a tubular container with circular cross-section, in Fig.11b a cross-section different over the height having bulbous tubular container with oval cross section and in Fig. 11c an angular container with rounded corners and a recessed grip shown with an angular cross section. With these few examples only be demonstrated that any shape of container and Cross sections also using beads, excellent or deepened Reliefs, with recessed grips, etc. can be produced, which contrasts the area of application conventional method for the production of tubular containers greatly expanded.

Materials such as PET are suitable for carrying out the process Polyethylene terephthalate, PEN = polyethylene naphthalate, PEP = polypropylene and Mixtures of PET / PEN, the list of materials is not exhaustive is.

There is also the possibility of inserting one or more into the open blow mold 16a, b Introduce labels, which are then firmly connected to the finished container 23 at the end are, which may save a separate labeling process.

Below is a concrete embodiment for producing a tube from PET = polyethylene terephthalate with a diameter of 50 mm and a length of 200 mm specified. The respective preforms with a diameter of 28 mm, one Wall thickness of 3 mm and a height of 66 mm with or without beads are set to 90 heated to 100 ° C, and only in the zones where they are stretched and blown have to. The drawing stretch takes place at a speed of 0.3 - 0.5 m / sec, whereby a pre-blowing pressure of 3 to 10 bar by supplying blowing air through the blowing nozzle 17 is observed. Subsequently, with an increased blowing pressure of 30 to 40 bar the molding of the preform on the wall of the blow mold 16a; 16b causes. At the same time, the blow mold 16a; 16b cooled to about 10 ° C, the cooling time of Influence time of the blowing pressure at 30 to 40 bar corresponds. It is approximately 0.8 to 1.2 seconds. Venting the finished tube takes about 0.3 to 0.4 seconds, resulting in one Wall thickness of the finished tube from 0.15 to 0.4 mm is achieved.

Claims (12)

1. Method for producing containers (23) by separate production of a preform (1) with a neck (4) with definitive dimensions and a tubular body (2) with smaller dimensions relative to the proposed definitive form, heating the preform (1), fastening the preform (1) in the neck region on a drawing head (9b), introduction of the preform (1) with the drawing head (9b) into the interior of a multi-part closable blow mould (16a; 16b), axial drawing of the preform (1) by means of the drawing head (9b) and expansion of the preform (1) by the supply of blowing air into the interior thereof, curing the container resting on the wall of the blow mould (16a; 16b), aperture the blow mould and removing the container, characterised in that to produce a tubular container (23) the preform (1) comprises at one end a closure and at the other end an open filling aperture (3) with an exterior projecting flange (6) and the preform (1) is connected to the drawing head (9b) in a rotatable manner relative to one another, the blowing air being supplied by means of a blow nozzle (17) arranged in a sealed manner at the open end of the filling aperture (3), the flange (6) being held in a clamped manner on the blow nozzle (17) and in that the incompletely inflated or stretched lower end part (19) of the container (23) produced is separated or cut to length.
2. Method for producing tubular containers (23) according to claim 1, characterised in that the preform (1) comprises a discharge aperture (7) in the neck (4).
3. Method for producing tubular containers (23) according to claim 2, characterised in that the discharge aperture (7) is produced after completion of the container mould.
4. Method for producing tubular containers (23) according to any one of claims 1 to 3, characterised in that the incompletely formed end part (19) is separated by a blade (20).
5. Method for producing tubular containers (23) according to any one of claims 1 to 3, characterised in that the incompletely formed end part (19) is separated by means of laser beams (21).
6. Method for producing tubular containers (23) according to claim 3 and 5, characterised in that the production of the discharge aperture (7) and the separation of the incompletely formed end part (19) take place in one operation using deflecting optics by means of laser beams (21).
7. Method for producing tubular containers (23) according to any one of claims 1 to 6, characterised in that the neck (4) can be fastened by means of an external thread (5) to an internal thread (10) of the drawing head (9b).
8. Method for producing tubular containers (23) according to any one of claims 1 to 7, characterised in that heating takes place irregularly over the height and or periphery of the preform (1).
9. Method for producing tubular contains (23) according to any one of claims 1 to 8, characterised in that the preform (1) is heated by radiant heat and/or hot air and/or ultrasound and/or microwaves.
10. Method for producing tubular containers (23) according to any one of claims 1 to 9, characterised in that the axial drawing takes place with the supply of blowing air in two stages by pre-blowing at a pressure of 3 to 10 bar and then at an increased blowing pressure of 30 to 40 bar.
11. Method for producing tubular containers (23) according to claim 10, characterised in that the blowing pressure is increased to 40 bar after the end position of the drawing head (9b) in the blow mould (16a; 16b) has been reached.
12. Method for producing tubular containers (23) according to any one of claims 1 to 11, characterised in that a label is introduced into an opened blow mould (16a; 16b).

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